Inverter assemblies are commonly employed in hybrid and electric vehicles to provide three phase operating power to an electric drive motor. In general, such inverter assemblies include a plurality of inverter switches mounted on a substrate. The inverter switches are electrically coupled between a direct current (DC) power source, such as a battery, and the electric drive motor by way of a bus bar. A capacitor may be electrically coupled between the bus bar and the DC power source to regulate fluctuations in voltage; however, depending upon the proximity of the capacitor to the switches, the capacitor may potentially induce voltage overshoots in the system. The inverter switches oscillate between open and closed positions to convert the direct current into alternating current (e.g., three phase alternating current) suitable for driving the vehicle's electric drive motor.
During operation of the inverter assembly, the inverter switches, the bus bar, and the capacitor generate heat and may consequently require thermal regulation to ensure proper functioning. For this reason, the inverter assembly may be provided with a liquid-cooling system, which actively circulates a dielectric coolant fluid over the active switches. However, the dielectric fluid may not contact and cool the bus bar, which is spatially offset from the substrate and the inverter switches. As a result, the liquid-cooling system may not achieve optimal cooling.
It should thus be appreciated that it would be desirable to provide a liquid-cooled inverter assembly having a substrate with an integrated bus bar wherein the cooling system directs coolant over the inverter switches, the substrate, and the integrated bus bar to thereby cool the inverter assembly in a more efficient manner. It would also be desirable if the liquid-cooled inverter assembly included a capacitor and a means for the cooling thereof (e.g., a heat sink). Preferably, the liquid-cooled inverter assembly would be configured such that the capacitor resides proximate the substrate and inverter switches so as to minimize inductive interference. Furthermore, other desirable features and characteristics of the present invention will become apparent from the subsequent detailed description and the appended claims, taken in conjunction with the accompanying drawings and the foregoing technical field and background.